It is known that when certain long chain alkyl quaternary ammonium salts are deposited on human hair, they improve combability i.e. the relative ease with which hair can be combed, by imparting a certain lubricity to the hair as well as by providing an antistatic effect. Both of these effects combine to make the hair easier to manage so that the desired appearance of the hair can be more readily achieved. Compositions having these properties are called "hair conditioners". See, for example, A. C. Lunn and R. E. Evans, The Electrostatic Properties of Human Hair, J. Soc. Cosmet. Chem., 28, 549 (1977).
These hair conditioners appear to function because they are cationic and are easily absorbed on the anionic surface of the human hair. However the conditioning effect is usually short lived because the conditioners wash out of the hair and are substantially eliminated after only a few washings.
The art has made many efforts to overcome the problem and provide durable hair conditioners which will stay on the hair despite hair washings.
Hannen et al in U.S. Pat. No. 4,299,817 describe an aqueous composition for setting hair which contains as the active ingredient, a polyelectrolyte complex which is the ionic reaction product of one or more polycationic polymers and one or more polyanionic polymers.
Quaternary ammonium salts are also known for other purposes.
For example, U.S. Pat. No. 3,510,248 to Thielan et al discloses certain chloro quanternary compounds for softening cellulosic materials e.g. cotton textile fibers.
Matter et al in U.S. Pat. No. 3,844,867 describe the use cationic quaternary ammonium halides substituted with an alkylene halide group or an alkyl halide group interrupted with a phenylene group for improving the affinity of anionic dyes to textiles such as nylon.
Despite major efforts, however, the art has not yet provided durable hair conditioners which will continue their desirable effects in human hair through several shampoos.